This will be when above-ground growth is still green ... If you're short of space, try growing potatoes in an adequately drained container that's at least 30cm (1ft) deep and wide.
As soon as your soil can be worked, your spuds can go in the ground ... in cooler weather, your potatoes won’t really get started growing until the soil is above 45 degrees Fahrenheit.
Milne famously declared that anyone who really likes potatoes ... from planting until harvest, and second earlies from 12 to ...
You can, of course, plant potatoes deeper in the ground but this will just mean more ... At this time of year, you can plant lettuce above potato tubers since lettuce will be ready for harvest ...